Method of making lined receptacles



Feb 3%5 w. E. MEKSSNER 39fl6 METHOD OF MAKING LINED RECEPTACLES Original Filed July 14, 1959 3,169,036 METHOD OF MAKENG LINED RECEPTACLES 8 Claims. Cl. 156-287) The invention relates to the manufacture of receptacles or cartons for use in packaging of flowable materials, and particularly to rigid receptacles having fluid impermeable unitary seamless linings.

This application is a division of United States patent application 827,099, filed July 14, 1959, and now abandoned.

In the packaging of flowable material, and particularly liquids, in containers which are not of leakproof materials or construction, the customary practice is to treat at least the internal walls thereof to render the same impermeable to fiuids. In the conventional paperboard milk cartons, for example, both the inner and outer carton walls are coated with a relatively heavy layer of wax. While waxcoated or similarly treated cartons are of economical construction, fiexing and/ or jarring of such cartons during shipment or even normal packaging operations tends to weaken, crack and chip the carton coating and often results in leakage of the package material. The presence of Wax or other coating chips in the packaged material of course creates considerable consumer objection and often may render the packaged material unsuitable for its intended use, as for example in the case of lubricating oil for precision equipment. Accordingly, a primary object of the invention is to provide a new or generally improved and more satisfactory method for making receptacles for packaging of fiowable materials.

Another object is the provision of an improved method for making rigid receptacles having integral fluid impermeable seamless linings.

Still another object is to provide a method for making a receptacle having an integral seamless lining, yet which may be readily collapsed or flattened for storage or transit without impairing the leakproof character of the lining itself.

A further object of the invention is to provide a method for making an improved collapsible carton having a seamless fiuid impermeable inner lining which is secured to only the carton side Walls thereby facilitating folding of the lined carton into a flattened condition.

A still further object of the invention is the provision of a simple and eflicient method of providing a substantially rigid receptacle with an integral seamless lining for use in packaging fluids which avoid the difiiculties of the breaking away of particles or chips of foreign material used in the coating of the receptacle, thereby avoiding contamination of the fluid contents with such foreign materials and reducing the danger of leakage.

These and other objects and advantages of the inven tion will be apparent from the following description and accompanying drawing in which:

FIGURE 1 is a diagrammatic view illustrating the mannor of applying a seamless lining to a receptacle in accordance with the method of the present invention, with the receptacle shown partly in section;

FIGURE 2 is a perspective view of the receptacle shown in FIGURE 1 in its finished condition, with the lining thereof projecting through and being sealed about a receptacle access opening;

FIGURE 3 is a perspective view showing a conventionalmilk carton lined in accordance with the procedure shown in FIGURE 1, with the lining thereof extending over and adhesively bonded to the carton flaps;

FIGURE 4 is a perspective view of an open end carton lined in accordance with the method of the present invention, with certain of the carton surfaces pretreated to prevent adhesion of the lining thereto; and

FIGURE 5 illustrates the finished carton of FIGURE 4 in its collapsed or flattened condition.

In general, the lined receptacles or cartons of the pressent invention are formed by suspending a gob of tacky plastic film-forming material within a receptacle and then inflating the gob into the form of a seamless envelope which engages with the receptacle walls and adheres to at least certain of the inner surfaces thereof. During the initial inflating operation, the gob of film-forming material is disposed adjacent to a closed or bottom wall of the receptacle until the expanding envelope of filmforming material engages with substantially the entire surface thereof, after which the gob is gradually moved or elevated toward and through an opening in the recep tacle concomitantly with continued inflation thereof. In this manner, the expanded envelope of film-forming material progressively engages with successive portions of the receptacle side walls, thus displacing the air from within the receptacle and providing a uniform seamless lining which snugly engages with substantially all inner surfaces of the receptacle.

The concomitant movement and inflation of the gob of film-forming material is continued until the resulting expanded envelope of film-forming material extends through and beyond the receptacle openin At this stage, movement of th gob of film-forming material is stopped while the inflating medium is continuously delivered to further expand the gob outwardly of the receptacle and until separation or severance of the envelope of film-forming material is effected. Preferably, the final expansion is effected by a surge of inilatim medium to cause a rapid severance of the expanded envelope of film-forming material and, perhaps more important, to urge the severed or open end portion of the expanded envelope laterally away from the receptacle opening and into engagement with the adjacent exterior surfaces of the receptacle itself. In addition to preventing an accumulation of the adhesive film-forming material along the receptacle opening, the continuity of the lining along and about the receptacle opening reinforces the same and minimizes the degree of care which must be exercised during subsequent receptacle-filling operations.

The gob of plastic film-forming material initially suspended within the receptacle may include an amount sufficient for lining the entire receptacle and opening therein. Alternatively, this initial gob of film-forming material may include only a portion of the necessary amount and may be continuously replenished concomitantly with the inflation thereof.

The present invention provides a simple, eflicient' and economical system for producing leakproof receptacles or cartons. The outer receptacle of the finished package may be of any desired size and shape and may be formed of any material, such as low cost, untreated paperboard. Since the main function of the outer receptacle is to conline the inner plastic envelope and provide the requisite structural strength, the receptacle itself need not be leakproof since this requirement is completely satisfied by the expanded envelope of film-forming material which lines substantially the entire inner surface thereof. The strength of the receptacle is, of course, such as to satisfactorily resist the particular handling which it is intended to receive but need not be so rigid as to resist all flexing and deformation since the lining thereof is quite flexible and can readily yield when the finished package is subjected to excessive impacts and/ or bending forces. Because of the adhesive character of the plastic filmforming material, there is no liability that parts of the lining will break off and mix with the packaged contents.

The receptacle lining may be made from a wide variety of materials which are of a tacky or adhesive character when rendered plastic or fiowable. Preferred types include the synthetic linear polymers of thermoplastic character and the elastomeric types. Examples include vinyl resins, such as polyvinyl acetate, copolymers of vinyl chloride and vinyl acetate, copolymers of acrylonitrile and vinyl acetate, polyacrylonitrile and copolymers of acrylonitrile with vinyl chloride, vinyl acetate, meth acrylonitrile, and so forth, polyethylene, linear superpolymers of the polyester of nylon (polyamide) type, polyvinyl butyral, polyvinyl alcohols, polyvinyl ethers; elastomeric types may include neoprene, polymers of chloroprene, copolymers of butadiene with styrene or acrylonitrile, polyisobutylene, and so forth. it is to be understood that the mentioning of these particular materials is not intended to limit the invention thereto but merely to illustrate the wide variety of film-forming materials that can be used in carrying out the invention. Of course, the selection of any particular material depends upon the character of the flowable material to be packaged. Thus, polyvinyl acetate, polyvinyl acetals and polyvinyl alcohols and neoprene, especially the latter two types, are highly advantageous when packaging oils, especially of the hydrocarbon type. Polyvinyl acetate, polyvinyl chloride, related copolymers of these two monomers, and polyethylene are, on the other hand, particularly adapted for packaging of aqueous liquids.

In view of the tacky nature of the film-forming materials employed, the envelope formed during inflation thereof will adhere to the surfaces of the receptacle against which the expanded envelope of film-forming material engages to provide for a unitary construction. In the manufacture of lined cartons which are to be subsequently collapsed or flattened for storage or transit, certain of the carton surfaces are pretreated to prevent adhesion of the expanded envelope of the film-forming material therewith thereby permitting such pretreated carton walls to be moved relative to the carton lining Without risk of lining rupture.

The film-forming material may be converted into a fiowable mass or gob by fusion or by the incorporation of plasticizers or solvents capable of dissolving or dispersing the material. Thus, any of the thermoplastic materials may be heated to fusion after which the infiat ing medium may be introduced into a gob thereof, preferably at the same temperature as the fused material. If necessary, the temperature of fusion may be lowered by the incorporation of a plasticizer either of solid or liquid character. When plasticizers or solvents are incorporated into the plastic material to form the gob, the plasticizer or solvent is preferably non-reactive with the inflating medium. The cooling of the fused plastic mass, with or without plasticizers, is effected as the expanded envelope strikes the Wall of the receptacle where it is set into a desired shape conforming to the walls of the receptacle. Volatile solvents may be employed for dissolving or dispersing the film-forming material so that the gob may be formed at room temperature and expanded, with the setting or coagulation of the expanded envelope occurring by volatilization of the solvent after expansion thereof against the receptacle Walls. Known solvents and plasticizers may be employed, the selection depending upon the particular film-forming material to be used. Thus, acetone or dioxane may be used for vinyl acetate or copolymers of vinyl acetate or vinyl chloride or acrylonitrile. The concentration of the film-forming material, when a solution thereof is used, is preferably as great as possible and is limited only by the necessity that the plastic mass be capable of expanding under the pressure of the inflating medium, yet be of a reasonably viscous Al. coherent plastic character which is capable of supporting its own weight.

The inflating medium may be air or other gas which is non-reactive with the filrn-forming material. As heretofore mentioned, the inflating medium is preferably heated when delivered into the gob of film-forrning material to prevent premature setting thereof. in lining of large receptacles, it may be further desired to effect the lining with the receptacle itself being heated or disposed within a heated chamber.

With reference to FIGURE 1 of the drawing, the gob of film-forming material for lining of a receptacle 15 is carried at one end of a nozzle 17 which is of known construction and includes a pair of spaced concentric or telescoped tubes 19 and 21. The uppermost end of the tube 19 is connected to a supply of flowable film-forming material, with means being provided for delivering the film-forming material at a continuous or pulsating rate, as heretofore mentioned. The tube 21 is similarly con nected to a suitable pump or pressurized tank for delivering an inflating medium, such as air, in accordance with a predetermined flow pattern. The nozzle 17 is supported for vertical reciprocating movement, as for example by a rack and pinion, not shown, which will permit the nozzle to be gradually elevated at a desired rate.

The receptacle 15 may be of paperboard or like construction and is provided with a restricted access opening 23 formed centrally of its top wall and preferably reinforced with a metal grommet 25. To permit the escape of air from within the receptacle during the lining operation, as more fully described hereafter, the access opening 23 is appreciably larger than the cross-sectional dimension of the nozzle 17. The receptacle access opening 23 may be readily closed by a stopper to thus provide a highly satisfactory receptacle for use in packaging of liquids or dry granular materials without requiring numerous carton bending or folding operations.

In the lining of the receptacle 15, the nozzle 17 is initially moved through the receptacle opening 23 into a position adjacent to the receptacle bottom wall, as illustrated in FIGURE 1. The plastic film-forming material is then supplied through the tube 19 to form a gob thereof at the tip of the nozzle 17, as shown in dotted lines at 27, where it covers the adjacent end of the tube 221. The infiating medium is then supplied through the tube 21 to effect a continuous expansion of the gob of plastic filmforming material into the form of an envelope as shown at 239. During this initial stage of the receptacle lining procedure, the nozzle 17 is maintained stationary as the continuously expanding envelope of film-forming material engages with and adheres to the receptacle bottom wall. As the expanded envelope of film-forming material moves into the receptacle corners, as shown in the drawing, the nozzle 17 is gradually but continuously elevated toward and through the receptacle access opening 23 concomitantly with the continuous delivery of inflating medium.

The gradual upward movement of the nozzle 17 is correlated with the delivery rate of the inflating medium so that the expanding envelope of film-forming material progressively engages with and adheres to successive portions of the inner surfaces of the receptacle to line the same as shown at 33. As the envelope of film-forming material progressively engages with these receptacle surfaces, the air within the receptacle is displaced upwardly and out through the access opening 23, thus preventing the formation of air pockets between the lining 33 and the receptacle walls. As heretofore mentioned, the gob of film-forming material initially supplied .to the tip of the nozzle 17 may include the necessary amount for lining the entire receptacle. Alternatively, the initially supplied gob of film-forming material may be just sufficient to start the formation of an envelope, and may be continuously replenished concomitantly with the expansion thereof.

The movement of the nozzle it? simultaneously with the inflation of the film-forming material is continued until the nozzle 17 is disposed outwardly of the receptacle. It will be noted that with this procedure, all internal receptacle surfaces, as well as the portion of the receptacle wall which defines the access opening 23, are lined with an integral seamless covering of film-forming material thus providing a unitary structure.

In its uppermost position, as shown in FIGURE 1, the nozzle 17 is maintained stationary while the inflating medium is continuously supplied to effect a further expansion of the film-forming material outside of the receptacle, as shown at 35, and into engagement with an annular cutting blade 37. As the envelope of film-forming material is separated from the nozzle 17, the severed edge portion thereof engages with and adheres to the top surface of the receptacle around the opening 23, as best seen at 39 of FIGURE 2. If desired, the final expansion of the film-forming material outwardly of the receptacle may be effected by a surge of inflating medium so as to cause severance of the envelope without the use of a cutting blade. Regardless of the manner of severing the envelope of film-forming material, it will be apparent that the escape of the inflating medium as the envelope is severed will cause the open end portion of the severed envelope to be snugly urged against and adhered to the outer surface of the receptacle adjacent to the access opening.

The extension of the receptacle lining to the outside of the receptacle itself, as described above, eliminates any tendency for the packaged materials to seep in-between the lining and the receptacle wall in the vicinity of the access opening 23. Further, since the lining is formed of inherently yieldable material, it will be apparent that the portion or" the lining extending about the access opening 23 will readily deform as a stopper or other closure is inserted therein to thus provide a fluid-tight seal.

While the method of the present invention has been thus far described withregard to the lining of receptacles having restricted access openings, it will of course be apparent that the described procedure is equally applicable and satisfactory for use with receptacles of other construction. As shown in FIGURE 3, for example, the above-described procedure may be employed in providing a conventional open-end milk carton 41 With a continuous seamless lining 43 which projects outwardly of the carton itself. The lining 43 actually consists of an envelope of film-forming material which has been gradually and progressively expanded against the inner surfaces of the carton 41 in a manner as heretofore described. As with the structure shown in FIGURE 1, the formation of this envelope of film-forming material is continued to a point above the open end of the carton 41 where it has been severed, as for example by a cutting blade or by a surge of inflating medium. Once severance of the envelope of film-forming material is effected, the free end portions thereof extend over and adhere to the adjacent exterior surfaces of the carton walls.

In view of the yieldable nature of the seamless lining 43, the lined carton 41 is adapted to withstand greater shocks than the conventional wax-coated milk cartons, and provides further assurances that the packaged contents will be free of foreign particles. Further, in view of the continuity of the lining to the outside surfaces of the carton, seepage of the material being packaged in-between the lining and carton wall is prevented. The lined carton 41 is closed in the usual fashion by pleating the upper portion of the side walls along crease lines 45 and 47 after which carton flaps 49 are placed together and folded over. In lieu of securing the flaps 49 with a staple, as in the usual milk carton construction, the portion of the lining 43 on the carton flaps 45 may be merely heated and pressed together to provide a strong fluid-tight seal.

FIGURES 4 and 5 of the drawing illustrate the applicability of the method of the present invention to cartons which are intended to be flattened or collapsed for storage or transit after being lined. In this construction,

a conventional paperboard carton 51 having end flaps 53 and 55 is provided with a continuous seamless lining 57 in a manner similar to that employed in the lining of the receptacles l5 and 41 heretofore described; that is, by expanding a gob of film-forming material into a seamless envelope which gradually and progressively engages with the inner carton surfaces. Prior to the lining operation, the end flaps $3 and 55 at one end of the carton are temporarily folded over each other, but not sealed, to form a closed or bottom wall. The inner surfaces of the carton bottom wall (the exposed surfaces of the flaps 53 in FIG- URE 4) are pretreated either before or after this folding step, as for example by dusting with talc as shown at 59, to prevent adhesion of the envelope of film-forming material therewith. The flaps 53 and 55 at the opposite end of the carton 51 are preferably held in upstanding positions by a retainer 61, and are also pretreated or dusted with talc along their inner surfaces, and if necessary along their outer surfaces also, as shown at 63.

During the lining of the carton 51, the expanding envelope of film-forming material gradually and progressively engages with successive inner portions of the carton walls, thus displacing the air from within the carton and providing the carton walls with a unitary seamless lining. It Will be noted that as the film-forming material is expanded within the upper portion of the carton 51, the upstanding end flaps 5'3 and 55 serve to confine the expanding envelope of film-forming material without adhering thereto. As in the receptacle constructions heretofore described, the envelope of film-forming material is severed above the open end of the carton 51 thus providing the finished carton with a free liner portion 65 which may be gathered, after the lined carton is filled, and tied or heat-sealed to contain and separate the packaged material from the outer rigid carton itself.

Sincethe lining 5'7 is not bonded to the flaps at either end of the carton, the flaps 53 and 55 forming the temporary bottom Wail of the carton fill may be now moved into alignment with the respective carton side walls and the carton itself may be collapsed into a position as shown in FIGURE 5. In View of the inherent yielding characteristics of the lining material, it will be noted that the unadhered bottom portion of the lining 57 can readiiy deform during the carton-collapsing operation without risk of rupturing the lining itself. To further assure that the carton lining 57 will not tear as the carton is collapsed, the inner surfaces of the carton side Walls adjacent to the closed end of the lining may be also pretreated with talc or the like to prevent adhesion of the lining thereto. For example, the inner surfaces of all of the carton corners adjacent to closed end of the lining, or at least the diagonally opposite corners which are moved away from each other during collapsing of the carton may be pretreated with talc as shown at 6'7 in FIGURE 4. With this provision for additional slack the lined carton 51 can be collapsed without inducing any stresses in the closed end of the lining itself.

As is apparent from the above description, the method of the present invention facilitates the production of fluid impermeable lined receptacles in a. simple and eflicient manner. Further, the steps of the present method can be easily varied so that receptacles of varied size and shape can be readily lined with highly satisfactory and uniform results.

While preferred embodiments of the invention have been shown and described, it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A method of lining a receptacle having side walls which are adapted to be moved toward and away from each other for urging the receptacle into collapsed and erect positions, respectively, a closed end, and end flaps defining an opening at the opposite end thereof including .expand the same into the form of a seamless envelope which engages with and covers the closed end of the receptacle, gradually moving the gob of plastic film-forming material toward the receptacle opening concomitantly .with continued expansion thereof to progressively urge the expanding envelope of film-forming material into engagement with the receptacle side walls, allowing the expanded envelope of film-forming material to set and adhere to the receptacle walls, and severing the expanded envelope of film-forming material from the gob thereof outwardly of the receptacle opening, said lining being free of the closed end of the receptacle whereby the receptacle may be collapsed and erected without risk of lining rupture.

2. A method as defined in claim 1 wherein selected corner portions of said receptacle side walls adjacent the closed end thereof are pretreated to prevent adhesion of the envelope or" film-forming material therewith.

3. A method as defined in claim 1 wherein the end flaps defining the receptacle opening are pretreated along the inner surfaces thereof prior to expansion of the filmforming material to prevent adhesion of the expanded envelope therewith.

4. A method of providing a collapsible carton having side walls and end flaps with a liquid impermeable lining including the steps of folding carton end flaps into over lapping relationship to provide the carton with a closed end, treating at least the exposed surfaces of the innermost flaps which form the closed end of the carton to prevent adhesion of a tacky film-forming material thereto, passing a gob of tacky film-forming material through an open end of the carton and suspending the same therein adjacent to the closed end thereof, delivering a gas under pressure into the gob of tacky film-forming material to inflate a portion of the same into the form of a seamless envelope which engages with the closed end of the carton, gradually moving the gob of tacky film-forming material toward the open end of the carton concomitantly with continued inflation thereof to progressively urge the envelope of film-forming material into engagement with adjacent carton walls, allowing the expanding envelope of film-forming material to set and adhere to the carton walls, continuing the movement and concomitant inflattion of the gob of film-forming material to extend the inflated envelope through and outwardly of the open end of the carton, and severing the inflated envelope from the remaining portion of the gob of tacky film-forming material by maintaining such remaining portion stationary while continuing the delivery of the gas under pressure.

5. A method as defined in claim 4 wherein selected corner portions of said carton side walls adjacent to the closed end thereof are also treated to prevent adhesion of the envelope of tacky film-forming material thereto.

6. A method as defined in claim 5 wherein the open end of the carton is defined by a plurality of end flaps, the inner surfaces of which are also treated to prevent adhesion of the envelope of film-forming material thereto.

7. A method of lining a collapsible carton having side walls, a closed end and end flaps defining an open end including the steps of disposing said end flaps in the planes 'of the respective carton side Walls, treating the inner surfaces of said end flaps to prevent adhesion of a tacky film-forming material thereto, passing a gob of tacky filmforming material through said open end of the carton and suspending the same therein adjacent to the closed end thereof, delivering a gas under pressure into the gob of tacky film-forming material to inflate a portion of the same into the form of a seamless envelope which engages with the closed end of the carton, gradually moving the .gob of tacky film-forming material toward the open end of the carton concomitantly with continued inflation thereof to progressively urge the envelope of film-forming material into engagement with adjacent carton walls, allowing the expanding envelope of film-forming material to set and adhere to the carton walls, continuing the movement and concomitant inflation of the gob of film-forming material to extend the inflated envelope through and outwardly of the open end of the carton, and severing the inflated envelope from the remaining portion of the gob of tacky film-forming material by maintaining such remaining portion stationary while continuing the delivery of the gas under pressure.

8. A method of lining a collapsible carton having a plurality of side walls which are hingedly connected to each other along their side edges for movement toward and away from each other as the carton is urged into collapsed and erect positions, respectively, and end flaps projecting from the opposite ends of at least certain of the side walls and adapted to be folded into overlapping relationship to provide carton end Walls, including the steps of erecting the carton with the flaps at one end thereof disposed in the planes of the respective side walls and the flaps at the other end thereof in overlapping relationship, treating the exposed inner surface of the flaps at opposite ends of the carton to prevent adhesion of tacky film-forming material therewith, passing a gob of tacky plastic film-forming material through the open end of the carton and suspending the same therein adjacent to the closed end thereof, delivering an inflating medium into the gob of plastic film-forming material to expand portions of the same into the form of a seamless envelope which engages with the closed end of the carton, gradually moving the gob of plastic film-forming material toward the open end of the carton concomitantly with continued inflation thereof to progressively urge the expanding envelope of film-formed material into engagement with the adjacent carton walls, allowing the expanded envelope of film-forming material to set after it engages with the carton walls, continuing the movement and concomitant inflation of the gob of film-forming material to extend the inflated envelope through and outwardly of the open end of the carton, and then increasing the rate of delivery of the inflating medium to inject the same as a surge to thereby sever the portion of the expanded envelope located outwardly of the carton and urge the same radially outward and into engagement with the surfaces of the adjacent carton flaps.

References Qited in the file of this patent UNITED STATES PATENTS 2,128,239 Ferngren Aug. 30, 1938 2,177,919 Vogt Oct. 31, 1939 2,317,763 Hall Apr. 27, 1943 2,805,787 Sherman Sept. 10,

2,872,760 Meissner Feb. 10, 1959 2,898,972 Strong Aug. 11, 1959 

1. A METHOD OF LINING A RECEPTACLE HAVING SIDE WALLS WHICH ARE ADAPTED TO BE MOVED TOWARD AND AWAY FROM EACH OTHER FOR URGING THE RECEPTACLE INTO COLLAPSED AND ERECT POSITIONS, RESPECTIVELY, A CLOSED END, AND END FLAPS DEFINING AN OPENING AT THE OPPOSITE END THEREOF INCLUDING THE STEPS OF TREATING THE INTERNAL SURFACE OF THE CLOSED END OF THE RECEPTACLE TO PREVENT ADHESION OF A TACKY FILMFORMING MATERIAL THERETO, SUSPENDING A GOB OF TACKY PLASTIC FILM-FORMING MATERIAL WITHIN THE RECEPTACLE AND ADJACENT TO THE CLOSED END THEREOF, DELIVERING A GAS UNDER PRESSURE INTO THE GOB OF PLASTIC FILM-FORMING MATERIAL TO EXPAND THE SAME INTO THE FORM OF A SEANLESS ENVELOPE WHICH ENGAGES WITH AND COVERS THE CLOSED END OF THE RECEPTACLE, GRADUALLY MOVING THE GOB OF PLASTIC FILM-FORMING MATERIAL TOWARD THE RECEPTACLE OPEING CONCOMITANTLY WITH CONTINUED EXPANSION THEREOF TO PROGRESSIVELY URGE THE EXPANDING ENVELOPE OF FILM-FORMING MATERIAL INTO ENGAGEMENT WITH THE RECEPTACLE SIDE WALLS, ALLOWING THE EXPANDED ENVELOPE OF FILM-FORMING MATERIAL TO SET AND ADHERE TO THE RECEPTACLE WALLS, AND SEVERING THE EXPANDED ENVELOPE OF FILM-FORMING MATERIAL FROM THE GOB THEREOF OUTWARDLY OF THE RECEPTACLE OPEING, SAID LINING BEING FREE OF THE CLOSED END OF THE RECEPTACLE WHEREBY THE RECEPTACLE MAY BE COLLAPSED AND ERECTED WITHOUT RIDK OF LINING RUPTURE. 